WebSockets vs REST API for Chat Widgets
Building a chat widget? You’ll need to decide how messages get sent and received—WebSockets or REST API. One is real-time and always connected. The other is request-based and easier to manage.
Here’s a breakdown to help you decide.
Quick Comparison Table
| Feature | WebSockets | REST API |
|---|---|---|
| Message Delivery | Real-time | Delayed (unless polling) |
| Connection Type | Persistent (always open) | One request at a time |
| Best Use Case | Live chat between users | Prompt → response (AI) |
| Server Load | Lower with many messages | Higher if polling |
| Complexity | Higher | Lower |
| Supports Typing Indicators | Yes | No |
| Works Offline | No | Yes (for sending, with retry) |
When to Use WebSockets
WebSockets are the better choice for real-time human chat. Once a connection is open, the server and client can talk to each other at any time.
Use WebSockets if you want:
- Instant message delivery
- Typing indicators
- Online/offline presence
- Live support chat
- Group messaging
Pros of WebSockets
| Benefit | Description |
|---|---|
| Real-time communication | Messages are sent/received instantly |
| Lower latency | No need to check for new messages |
| Fewer requests | Connection stays open |
| Rich features | Enables live feedback, typing, presence |
Cons of WebSockets
| Drawback | Description |
|---|---|
| More setup | Requires stateful servers and connection handling |
| Harder to scale | Needs WebSocket-aware infrastructure |
| Not ideal for short tasks | Overkill for one-time data fetches |
When REST API Works Best
REST is request-response. It’s perfect when you send a message and wait for an answer, especially in AI chat.
Use REST if:
- You’re integrating with AI (like OpenAI)
- You just need to send a message and get a reply
- Real-time feedback isn't required
Pros of REST API
| Benefit | Description |
|---|---|
| Simpler infrastructure | Easy to scale with serverless or stateless apps |
| Widely supported | Works with almost any backend system |
| Good for one-time tasks | Like login, file upload, or fetching history |
Cons of REST API
| Drawback | Description |
|---|---|
| Not real-time | Needs polling to receive new messages |
| Slower chat experience | Feels delayed without streaming or tricks |
Why AI Models Use REST APIs
AI models like OpenAI’s don’t need a live connection. You send a prompt, the model replies. That’s it.
Here’s why REST makes more sense for them:
| Reason | Explanation |
|---|---|
| Simpler client interaction | Send request, get response |
| Scalable | Easier to handle millions of users |
| No need for real-time | Responses take time anyway |
| Streaming over HTTP | Simulates live typing without WebSockets |
Even when AI services want to make things feel faster, they use HTTP streaming, not WebSockets.
Final Recommendation
| Use Case | Best Choice |
|---|---|
| Human chat (real-time) | WebSockets |
| AI chat (prompt → response) | REST API |
| Mixed use (chat + features) | WebSockets + REST |
Use WebSockets when you need fast, live updates. Use REST when you just need to send a request and wait. Most chat apps combine both—REST for setup, WebSockets for the live chat part.
Pick the tool that fits the job, not just the trend.
